Conventional chain guards cover only the top of the chain and do not protect trouser leg material, shoelaces and other clothing or barefeet from picking up grease stains or becoming caught in the mechanism throughout the 360.degree. rotation of the chain sprocket. Conventional chain guards do not cover the derailer, a particular hazard-prone device on multi-speed systems. Early prior art patented sprocket shields such as disclosed in U.S. Pat. Nos. 504,121, 675,502, and 1,136,411 are rigid and not universally applicable to all types of sprockets. A later U.S. Pat. No. 3,477,303 discloses a two sprocket assembly having an annular chain guard formed as a rigid stamping adapted for non-universal original equipment installation and U.S. Pat. No. 3,815,439 likewise discloses rigid stamped chain guard members for original equipment manufacture which are not universally applicable or flexible.